Process for the intensive aftertreatment of synthetic threads



Jan. 30, 1951 Filed April 1, 1948 F. A. PROCESS FOR THE INTENSIVE AFTERTREATMENT J. VAN HALL ET AL 0F SYNTHETIC THREADS 3 Sheets-Sheet l QZZM yW MW Jan. 30, 1951 F. A. J. VAN HALL ET AL' 2,539,980

PROCESS FOR THE INTENSIVE AFTERTREATMENT 0F SYNTHETIC THREADS Filed April 1, 1948 5 Sheets-Sheet 2 Jan. 30, 1951 Filed April 1, 1948 F. A. J. AN HALL ET AL- PROCESS FOR THE NTENSIVE AFTERTREATMENT OF SYNTHETIC THREADS 3 Sheets-Sheet 5 Patented Jan. 30, 1951 UNITED STATES PATENT OFFICE PROCESS FOR THE INTENSIVE AFTER- TREATMENT OF SYNTHETIC THREADS Floris Adriaan Jan van Hall and Daniel Rogla Barcelo, Barcelona, Spain, assignors to American Enka Corporation, Enka, N. 0., a corporation of Delaware Application April-1, 1948, Serial No. 18,408 in Spain April 12 1947 I liquid treatment of a linearly moving thread.

More specifically the invention concerns the efifecting of after treatments with different treat- :ing liquids sequentially on continuously moving threads.

When manufacturing rayon according to the "wet spinning process, the spinning solution, for example viscose, is extruded by means of a spinneret into a spin bath. The-thread formed there- .in is coagulated and partially regenerated in the .spin bath or the regeneration may be substantially completed in a complementary second bath. During the treatment in the second bath, while the thread is being decomposed into cellulose hydrate, a stretching operation is often applied. Finally, the thread is wound on bobbins or collected in a centrifugal bucket.

In this customary'process the thread, after being collected on bobbins or in cakes, must be submitted to after treatments in order to remove the residual salts and impurities deposited during the manufacturing process. These treatments comprise deacidifying, bleaching, washing, and :finally, drying.

Although the above referred to standard process has been developed to a highly efficient point, certain disadvantages are still present therein.

Certain disadvantages of the standard process are found to occur in the liquid after treatments. Additionally the process is objectionable in that during the formation of the thread package, irregularities occur in the thread. This is inherent in the process for the reason that it is practically impossible to coagulate "and after treat all parts of the thread under the same conditions. The action of the after treatment'baths is not uniform throughout all portions of the package, particularly in the extreme interior and exterior por- 'tions thereof. During the drying of the packages as normally produced and treated, diiierences in tension are created within the packages which effect diiferent degrees of contraction therein and cause irregularities to exist in the final products.

Ina-n effortto'improve the physicaland chemical properties of thethread, :the synthetic textile industry has resorted to what is known as continuous spinning, and various schemes have been proposed to pass the thread continuously through the different baths for coagulation; and after aeat entg Some of these processes" are based upon the-immersion the thread in successive reservoirs containing the desired liquids; others are based upon the wetting of the thread as it is passed over a number of complicated rotatable reels which are operated in such a manner as to cause the thread toprogress axially of the reels in a multiplicity of convolutions. Another process involves the treatment of the thread while it is passed axially of two angularly disposed cylinders, means being provided to apply the particular treating liquid to each of the respective sets of cylinders and the arrangements being such 'thatthe liquids are moved in a direction opposite to the direction of progression of the thread convolutions. Means are further provided to maintain the treating liquids separate after the application thereof to the thread.

A more recent proposal involves liquid sprays which are projected onto the thread at an angle by means of a power nozzle. The thread to be thus treated passes upwardly between two driven godets and the nozzles are formed with thread guiding grooves, the walls of which bear against the thread adjacent the point of projection of the liquid thereon. This proposal is ineffective for a number of reasons. To maintain the thread against the walls of the guides as the liquid is projected )thereon requires that the thread :in

traveling upwardly at an angle to the vertical be under high tension. The liquid which is projected upon the thread atan angle as it is thus propelled under high tension largely falls away andhas little effect on the thread. Due to the tension, the liquid will not have ready access to the individual filaments of the thread bundle and it will not properly penetrate and treat the same. Additionally the walls of the guiding groove contacted by the thread prevent the liquid from filming and forming a substantial sheath around the periphery of the thread. All of these factors tend to defeat the purpose of the treatment, and the effect of such of the liquid as is retained 'by the thread is limited.

All of the former processes proposed for solving the problems encountered in this art are-of'a more or less complicated nature and require :a large and expensive-plant, both from the standpoint of construction and maintenance. On the contrary, the present process is characterized by its great simplicity, since it eliminates the necessity for employing complicated mechanism. Furthermore, standard rayon manufacturing machines maybe adapted for the new process with very little modification.

ii; process is leased upon the surprising cbse'r atfon that the action of a treating-liq- -relationshiptothe thread; i 2

uid upon a moving thread becomes extraordinarily intensive under certain conditions, under which conditions the treating liquid penetrates and surrounds the component filaments of the thread bundle. These conditions may be summarized as follows:

The thread must be entirely free of any contact with any thread guides, supporting members, or other elements of the spinning machine which tend to hold the individual filament thereof in tight association from the point where the liquid contacts the thread to the treatment bath from which the thread emerges.

2. The liquid should be applied to the threa at an extreme point in its upward path of travel, 1. e., the ascending thread is contacted with a stream of liquid moving in a counter-current direction.

3. The filaments constituting the thread must be untwisted and in parallel relationship.

4. The thread must be under a low tension.

5. The thread must ascend in a substantially vertical path.

If the above conditions are met, the liquid surrounds the thread in the form of a sheath and penetrates between the individual filaments. The thread takes a very characteristic shape in the path Of treatment, namely, the thread appears to be many times thicker, which is apparently due to the adherence and absorption of the liquid thereon, causing an intensive swelling of the thread. Under these circumstances the action of the treating liquid is rendered much more rapid and eifective, so that when the thread moves at a speed of over 60 meters per minute, the threads vertical path does not have to exceed '70 cm. in order to realize a complete coagulation, desulphurization or other desired treatment. The reaction speed is attributed to the fact that the contact surface of the thread, or better said, of the elementary filaments, with the liquid is at a maximum.

Providedthe above set forth conditions are strictly adhered to, this intensive action of the liquid is equally striking in various kinds of after treatments, such as in the removal of salts, deacidification, washing, desulphurization, possibly removal of copper, bleaching, anti-chlorine treatment, and different types of finishing operations. In effecting the several difierent after treatments in a continuous operation the jets or streams of the liquids are applied successively, the treatments normally corresponding to the respective bath treatments utilized in the production of the particular synthetic thread involved in th various commercial operations.

The liquid treatment step of the invention may be utilized in any system or operation where it is desired to intensively treat a vertically ascending thread, and whereas many modifications can be made in the difierent forms of apparatus utilized, the invention can be more fully understood by reference to the accompanying drawings, wherein:

Figure 1 is a schematic illustration in side elevation of one particular type of continuous spinning machine constructed in accordance with this invention in which the treating troughs and ring twisting device are shown in cross-section;

Figure 2 is aschematic view in perspective illustrating a liquid treating system constructed in accordance with this invention including the system for re-circulating the treating liquid in its Figure 3 is a detailed illustration of the mechanism intended to be used in the adjustments of the guiding rollers which control the spacing of the thread convolutions upon the driven rollers shown in the upper portion of Figure 1;

Figure 4 is a side elevational view of one of the liquid vessels provided with a depending liquid jet forming spout constructed in accordance with this invention which has' been found to be particularly suitable for use in the process, the manner in which th thread is enveloped with a sheath of liquid as it is passed upwardly within the space defined by the spout being illustrated;

Figure 5 is a top plan view of the structure illustrated in Figure 4 Figure 6 is an end view of the structure illustrated in Figure 4;

Figure '7 is a side elevational View of another type of liquid vessel and spout similar in purpose to the structure shown in Figure 4;

Figure 8 is a top plan View of the structure illustrated in Figure '7; and

Figure 9 is an end view of the structure illustrated in Figure 7.

In referring to the drawings in detail the thread or filament which is formed and after treated in the apparatus shown in Figure 1 is indicated at It. Thread I0 is formed by the extrusion of a spinning solution through a spinneret II into a spin bath contained in trough I2. The thread is led from the spin bath through a thread guide I3 to a driven roller I4. Thereafter the thread is passed to a small freely rotatable roller I5 following which it is wrapped several times around the two rollers. A roller I6 is mounted for free rotation within a collecting trough I! positioned adjacent to and in the same plane as trough I2. Roller I6 is utilized as a lower guide for the thread. The thread is passed to and around roller I6 from roller I l and then'upwardly to driven roller I8 which is of larger diameter than roller I4. Roller I8 is driven at the same R. P. M. by the same shaft (not shown) that drives roller I 4.

Due to the arrangement described the thread is stretched in its passage from roller I l around roller I6 to roller I8.

A series'of rollers I9, 20, 2I and 22 are axially aligned with rollers I4 and I8 and are driven by the same shaft. These rollers I9, 20, 2| and 22 are therefore rotated together with rollers I4 and I8 and they are of the same diameter as roller I8. Consequently, the peripheral speeds of the rollers I8, I9, 20, 2| and 22 are the same. Arranged directly below each of the rollers I9, 20, 2I and 22 are collecting troughs 23, 24, 25 and 26, respectively. These collecting troughs are arranged adjacent to trough I! in the same horizontal plane and the walls constituting the partitions for separating the troughs are designated as 21, 28, 29 and 39. A roller similar to roller I6 is mounted for free rotation in each of the collecting troughs 23, 24, 25 and 26, these rollers being designated as 3|, 32, 33 and 34, respectively.

After the thread II] has been passed to roller I8 it is passed to a freely rotating elongate roller 35 in axial alignment with roller I5 and it is then wrapped several times around rollers I8 and 35. Thread I0, after leaving roller I8, is passed around roller 3| in collecting trough 23 and thence upwardly around roller I9, after which it is wrapped several times around rollers 5 roller 32' in collecting trough 24. As the thread progresses through the machine it is led upwardly-from roller 32 around roller 20 and then several wraps of the threadare made around roller .35 and roller 26 before the thread is again passed downwardly to a point where it is led around roller '33. in collecting trough 25. In order to efiect additional treatments of the thread it is passed upwardly from roller 33 and wrapped several times around roller 2| and roller 35,, after which; it is passed around roller .34 in the last of the troughs illustrated and then upwardly and around roller 22.

In the liquid treatment section of the apparatus-as thus described, the thread [:0 in its-upward flight passes substantially vertically to rollers (-9, 211,21 and 22, respectively. During each of the upward flights of the threada treatin liquid is supplied thereto by means of liquid vessels provided with spouts, the vessels being designated as 36, 31, 38 and 39, respectively. A similar vessel 4!] may be utilized to supply liquid to the thread passing upwardly from roller IE but for the reasons hereinafter discussed any suitable means for supplying-a liquid to a moving thread may be utilized at this position. The vessels 36-48, inclusive, may be of the form illustrated in Figures -4'9, inclusive, although it has been found that the vessel illustrated in Figures '4-6, inclusive, is particularly well adapted for use as the treating vessel at 36, '31, :38 and 40. On the other hand, the vessel illustrated in Figures 7-9, inclusive, is particularly suited to be the treating vessel at 39.

The single vessel 36 and its circulation system are illustrated in Figure 2 and are exemplary of the remaining vessels and their associated systems illustrated in Figure 1. Vessel 36 is :formed with an upstanding cup portion 4| from the upper portion of Which-extends an elongated lip or spout 42. Lip 42 is arcuate in transverse cross-section and for a considerable portion of its length upwardly from its lower tip it is arrangedin a plane parallel to the path of travel of thread in its upward flight. The lip or spout 42 is made arcuate in cross-section so as to-par-tially encircle the thread for applying to the thread a counter-current moving sheath or envelope of treating liquid as the thread passes upwardly therethrough.

In Figure 2 the thread is shown in a single vertical flight in association with the roller 31 positioned in trough 23. The recirculating system includes a liquid reservoir 43. Treating liquid .is fed from the reservoir through pipe 44 provided with a cock :45 for controlling or shutting off the supply :as desired. Gup portion M is maintained in a fixed but adjustable position near the upwardly moving thread by means of a support '45 and a bracket 41. In use. the liquid is fed to the vessel 41 at a predetermined rate :and it overflows the depressed edge of the cup :portion and passes downwardly within the spout or 'lip '42 in the form of a gentle stream through which the ascending thread moves. Since the liquid surrounds the thread in its upward passage as an envelope or sheath, the thread is maintained in proper position with respect to the spout. The thread is propelled at a speed such that the treating liquid will flow countercurrent thereto as the liquid is carried downnwardly by gravity. The liquid will collect in trough 2 3. The recirculation pf the liquid inlay ibeso regulated that thetrdugh contains a 8. liquid bath at a level above roller .3l as .fllustrated in the. drawings. The liquid in each of the circulating Systems is. of the desired hainia mposition, dependi g pon the part cular treatment there pre erre and it is main ained uniiorm so. that uniformity will be had in all parts of the thread as it is continuously reated in the particular operation. The thread in its. vertical ;ifl;i;gh-t should be free of contact with guides below the vessel or immediately thereabove, that ;is, any guide employed above the! vessel should be of such a nature as to avoidi the closing of the thread and the pressing of the treating liquid therefrom.

The liquid in trough 23 may be continuously recirculated by being propelled through a pipe: line 48, valve .49 tov tank 43. The liquid during recirculationmay e purified and reg nerated as is, desired or. necess ry- Thread to being. propelled upwardly w thin. the lip or spout .42. isv passed so that it will not be damaged or closed by pressure from the wall of the lip or spout.

Referring now again to Figure 1, the thread ill, after having been passed through the liquid treating steps. in the apparatus is directed to roller 50 .and then around a drying roller It .is then passed to elongate, freely rotatable roller 52 and wrapped several times. around the rollers 51 and 52. Roller 5-1 which is utilized as adrying roller is frustoaconical in form to permit the contraction of the thread as it is passed over the two rollers. Roller .5l may be in the form of acylinder and may be heated on the interior by any suitable means. .The dried 'thread, is passed from: roller 5.! downwardly through .a. thread guide 53 and then over a flier which slides over a ring 54,. Ring 5.4 is mounted to, be raised and lowered in the normal manner in order to control the. winding pattern of threadsv laid up on bobbin 55. The ring twister is illustrated schematically in Figure ,1 as being driven by an electric motor 516 which may be adjusted at two speeds. ,A slip clutch 5] of the centrifugal force type is pro ided which permits slip to the desired degree.

In Figure 3 a support is illustrated which may be utilized in adjusting rollers l5 and with respect to rollers 14., I 8, I 9, 29, 2| and 22. The adjustment of this support will permit a change in the relative inclination of the axes of the two sets of rollers for the purpose of controlling the spacing of convolutions of the thread on the rollers. This is accomplished by pivoting shaft ,58 whichmay support rollers i5 and 35 at :59 to bracket 6.0.. Bracket 6,0 is fastened to the "mavchine frame, designated at 6 I, Adjustment screw 62 is threaded into-pivoted nut 63 which in turn .is secured to bracket .60, and the screw has its ,free end pivota lyanchored at 64-to the end piece of shaft 58.. Upon turning screw 62 by the wing head '65 shaft 58- will be caused to move about pivot 59 and accordingly adjust the inclination of the axis of rollers 15 and 35 toward or away from the axis-of rollers M, 1,8. I9, 211. 2;! and '22 to. the desired degree. Ill-he shaft for roller 52 may be similarly mounted for ad-ziustment.

It is to be noted that the thread, as illustrated in Figure 1, as it is propelled toand from the rollers 31,32, 33, and 34 is passed around the driven rollers .18, Ill, 20., 2| and 22, respectively, ,and "that these latter rollers are coaxial and are of the same diameter. Accordingly the thread as it is moyedqurin these liquid treat ments is under substantially no tension. As

has been previously pointed out, this is one of the conditions that is considered essential in order to efiect the intensive treatment of the thread contemplated by this invention. It' is for this reason that it has been stated that any means suitable for applying liquid to the thread passing from roller 16 to roller I8 will be sufficient since the thread during such passage is under high tension due to the difference in the diameters of rollers l4 and I8. However, in an operation in which stretching of the thread is not effected at this stage of the process, a vessel of the type contemplated by this invention may be utilized with the same eflicient results as are had in the remaining steps in which the thread is passed under substantially no tension. It has also been found possible under certain conditions to efiect more than one treatment of the thread within one ascending path of travel. This may be accomplished by positioning two of the liquid vessels one above the other in the aforesaid relationship to the thread. In such an operation the treating liquids must be such as will permit the mixture thereof. It has been found feasible when'it is desired in the production of viscose yarn to finish the thread immediately after desulphurization. In such an operation, therefore, the liquid vessel for applying the finishing liquid may be disposed in the upper portion of the threadv flight andthe liquid treating vessel for the washing operation may be positioned between the first vessel and the bath trough located vertically therebelow. Therefore in such operation the thread containing the desulphurizing agent is washed before it.is subjected to the action of thefinishing agent.

The treating vessel illustrated in Figures 4-6, inclusive, is formed with a supporting bar 66 Iwhichis. adapted to beclamped in a bracket mounted on the machine. The upstanding cup is illustrated at 61 and a depending lip or spout 68 merges with the cup at 69 below the upper surface of the cup. The inner portion"! of the spout extends parallel to the cup portion 61. The cup portion 61 has a conical lower end ll on which is provided a connection 12 for the reception of a flexible tube or other suitable liquid conductor. Spaced guides 13 extend out;- wardly over and beyond the spout from the upper edge of the cup portion 61 and these guides are so spaced that they tend to line up the thread upon any tendency of the same to jump beyond the edges of the walls M of the spout. The construction is such that the overflowing treating liquid is gently directed downwardly countercurrent to the passage of the thread and the spout is so constructed that the thread is opened and placed in a liquid sheath or envelope. This application of the liquid tends to draw the individual filaments apart and permit ready access of the counter-flowing liquid to each of the in;- dividual filaments of the upwardly moving thread. The nature of the curve of the wall of the spout is such that the liquid stream is caused to assume a form which will envelope and impregnate the thread without any tendency to press out the liquid or close the thread as it passes within the spout.

The vessel illustrated in Figures 7-9, inclusive, is formed with a supporting rod 15 which may be mounted in the same manner asthat of the vessel illustrated inFigures 4-6, inclusive. This vessel is provided. with a downwardly extending conical spout 16 which has an opening I1 vertically extending throughout its height. A connection fora flexible hose or other liquid supply conductor is illustrated at 18 and the liquid supplied through the conductor will accumulate in the conical spout 15. The liquid in the conical spout will form a sheath or envelope upon the thread when it is passed through the center of the spout. Opening 11 is utilized in threading up the machine. In the construction illustrated in Figures L9, inclusive, the thread is not readily displaced from the spout and a uniform operation may be had without encountering any tendency to close the thread by contact with the walls of the spout as the thread passes upwardly in counter-current movement with respect to the treating liquid.

The execution of the process to which the present application relates will be understood better by means of the following examples:

Example I A normal viscose spinning solution with 6% cellulose and 7% NaOI-I was coagulated in a sulphuric acid bath of 7% H2804 containing zinc salt and sodium salt and having a specific gravity of 1.3 at 20 C. This thread was subjected to a preliminary stretch treatment between the spinneret I l and the roller I8. Dilute sulphuric acid of 3% concentration at a temperature of about 85 C. was applied to the thread by the vessel 4 in the flight leading upwardly to the roller l8. (The effect of the dilute sulphuric acid is that of de-xanthating and coagulation. while swelling is produced in the bath within the tank I1.) At vessel 36 the thread was treated with pure water at atemperature of about C. and at vessel 31 it was subjected to a desulphurizing treatment by a solution of 1.5% sodium sulphide. At vessel 38 it was subjected to another washing treatment with water at a temperature of about 80 C. and

finally, at vessel 39, it was supplied with an emulwhich was maintained at a temperature of 125 C.

at a peripheral end speed of 50 meters a minute. With 20 turns along the cylinder 5|, a wholly finished thread having a high degree of uniformity of physical and chemical properties was produced.

The dry thread issuing from the drying cylinder 5| was passed through the thread guide 53, flier 54, and onto bobbin 55 for twisting. As the high speed at which the twisting spindle of bobbin 55 normally rotates presents difficulties when threading onto the ring, the motor 25 may be drivenat two speedsthe required take-up speed and the decreased speed used for threading up.

Example II Normal viscose prepared from cellulose having a low hemi-cellulose content was spun through normal spinnerets into a Muller bath to form 1100 denier rayon having 275 filaments. After leaving the spin bath, the thread was guided in a substantially vertical direction alternately over draw off rollers and through treating baths, and during each ascending passage the thread was subjected to the treatment with liquids by means of the liquid treating devices shown in the drawings, and then dried, twisted, and collected, as shown therein. In the first path of thread travel to roller I8 a 3% sulphuric acid solution at C. was applied to the thread. During thesubse'quent-steps of thegafter treatment the thread was treated respectively with water at 80 C., 1.5% sodium sulphide solution, water at 80 C., and finally a 2% finishing solution at vessels 36, 31, 38 and 39, respectively.

During each treatment the thread never deviated over 3 from the vertical. The length of path travel, that is, from the bath to the liquid treating device, was approximately 80 cm. The quantity of liquid supplied from each of the liquid treating devices was 600 0111. per min ute. Under these conditions the treatments were effected successfully and without any mishaps. The dried and twisted thread was neutral, had a high strength and could be used satisfactorily as tire yarn.

The process according to the invention, is not limited to the production of viscose rayon, as it is applicable to the spinning of any type of synthetic thread which may be spun according to the so-called wet spinning method wherein a series of liquid treating baths are employed. It is only essential that care be taken that an untwisted thread is passing under low tension through a substantially vertical path, and in this path the thread must not be in contact with any parts of the apparatus such as thread guides, rollers, etc.

What is claimed is:

1. In a method of intensively treating freshly spun synthetic threads according to the wet spinning process in which a spinning solution is extruded through a spinneret into a coagulating bath to form a thread consisting of a plurality of untwisted filaments and in which the thread is after treated and collected, the step which comprises propelling the thread in an upward direction in a substantially vertical path between two widely spaced guiding points while under a tension insufficient to eifect a stretching thereof, and in the upper portion of the thread path during its ascending passage between said points initially guiding a jet of after treating liquid into contact with the thread and for a relatively small portion of the thread path in countercurrent relation to the direction of the thread travel while avoiding any other contact of the thread between the guiding points whereby a 10 sheath of treating liquid envelopes the thread at the point of contact and moves downwardly along the thread during the major portions of its travel in the path and penetrates the individual filaments.

2. In a method of intensively treating freshly spun synthetic threads according to the wet spinning process in which a spinning solution is extruded through a spinneret into a coagulating bath to form a thread consisting of a plurality of untwisted filaments and in which the thread is after treated and collected, the steps which comprise propelling the thread in an upward direction in a substantially vertical path between two widely spaced guiding points while under a tension insuificient to effect a stretching thereof, and in the upper portion of the thread path during its ascending passage between said points initially guiding a jet of after treating liquid into contact with the thread and for a relatively small portion of the thread path in counter-current relation to the direction of the thread travel while avoiding any other contact of the thread between the guiding points, the movement of the thread being at such a speed that a sheath of treating liquid envelopes the thread at the point of contact and moves downwardly therealong to the lower end of the thread path thereby penetrating the individual filaments, collecting the treating liquid at the lower end of the thread path, and recycling the collected treating liquid.

FLORIS ADRIAAN JAN VAN HALL. DANIEL ROGLA BARCELO.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 2,317,152 Costa et al Apr. 20, 1943 2,351,110 Davidson et al June 13, 1944 FOREIGN PATENTS Number Country Date 515,127 Great Britain Nov. 27, 1939 

1. IN A METHOD OF INTENSIVELY TREATING FRESHLY SPUN SYNTHETIC THREADS ACCORDING TO THE WET SPINNING PROCESS IN WHICH A SPINNING SOLUTION IS EXTRUDED THROUGH A SPINNERET INTO A COAGULATING BATH TO FORM A THREAD CONSISTING OF A PLURALITY OF UNTWISTED FILAMENTS AND IN WHICH THE THERAD IS AFTER TREATED AND COLLECTED, THE STEP WHICH COMPRISES PROPELLING THE THREAD IN AN UPWARD DIRECTION IN A SUBSTANTIALLY VERTICAL PATH BETWEEN TWO WIDELY SPACED GUIDING POINTS WHILE UNDER A TENSION INSUFFICIENT TO EFFECT A STRETCHING THEREOF, AND IN THE UPPER PORTION OF THE THREAD PATH DURING ITS ASCENDING PASSAGE BETWEEN SAID POINTS INITIALLY GUIDING A JET OF AFTER TREATING LIQUID INTO CONTACT WITH THE THREAD AND FOR A RELATIVELY SMALL PORTION OF THE THREAD PATH IN COUNTERCURRENT RELATION TO THE DIRECTION OF THE THREAD TRAVEL WHILE AVOIDING ANY OTHER CONTACT OF THE THREAD BETWEEN THE GUIDING POINTS WHEREBY A SHEATH OF TREATING LIQUID ENVELOPES THE THREAD AT THE POINT OF CONTACT AND MOVES DOWNWARDLY ALONG THE THREAD DURING THE MAJOR PORTIONS OF ITS TRAVEL IN THE PATH AND PENETRATES THE INDIVIDUAL FILAMENTS. 